Container containing at least two solid materials, and use thereof

ABSTRACT

This invention relates to a container having at least one inlet and/or outlet and containing at least two different solids arranged in layers as well as the use of said container for preparing a dialysate. In particular, a flexible bag is described, having three layers of different solids, where the middle layer consists of a solid which is compatible with the two adjacent layers and thus forms a separating layer between the two other layers. The layers are secured in place during shipping by vacuum packing.

This invention relates to a container having at least one inlet and/oroutlet, said container containing at least two different solids arrangedin layers as well as the use of said container for producing a liquiddialysate.

For treatment of a patient suffering from renal insufficiency, dialysisis performed to treat patients suffering from renal insufficiency. Thisis performed either in the peritoneum or through extracorporeal dialysisor filtration of blood. These two methods have in common the fact thatdialysis fluids or dialysates take up the degradation products ofmetabolism. These dialysates usually contain high levels of sodiumchloride and other electrolytes such as calcium chloride or potassiumchloride, a buffer substance such as bicarbonate or acetate and acid toestablish a physiological pH plus optionally glucose as an osmoticagent.

Dialysates are either supplied as ready-to-use solutions or they areprepared on site from concentrates, including solid concentrates. Solidsoffer the advantage of a small package volume and a low weight. Althoughsolids also have disadvantages—electrolyte salts, for example, arehighly hygroscopic—there is a trend toward offering only solidcomponents for preparation of dialysates.

The solids are usually salts or crystals which may be in powder form orin granular form. European Patent EP 0 287 987 describes a granularmixture of the ionic components needed for preparation of a dialysate.German Patent DE 43 03 372 describes a bag for holding solid or liquidconcentrate, usually of bicarbonate, which is used for preparing thedialysate and is connected directly to a dialysis machine.

Only components that will not react during their storage or otherwiseinfluence one another through their chemical and/or physical properties,i.e., substances that are mutually compatible, are stored together inone container. Substances which under some circumstances can under somecircumstances influence one another's chemical and/or physicalproperties are called incompatible substances. The lack of compatibilityneed not occur spontaneously but may also occur during a process towhich the components are usually subjected, such as sterilization ofdialysates.

To overcome this problem, separate storage has been preferred, whetherin separate containers or containers having multiple compartments, sothat the substances are mixed only shortly before the treatment.However, this results in other problems such as the problem of creatinga connection system between the sterile containers or the individualcontainers of the dialysis machine, whether by joining key-and-lockconnection systems that fit together, by breaking open a connectingchannel or by tearing open a peelable seam. In addition, it is possiblethat the joining of the individual components may not be complete and/oronly one of the components may be administered.

The object of the present invention is therefore to provide a containerwhich avoids the disadvantages that have become known in the state ofthe art. This object is achieved through the features of the firstclaim.

Characteristic of this invention is the layered bed of at least twosolids within a container. The solids should preferably be componentsfor a dialysate and are in the form of a powder, crystals or granules,because the dialysate components are prepared from salts or glucose. Thesolids contained in it may be water-soluble but need not be. In the caseof solids that are to form components of a dialysate, they are of coursewater-soluble. In addition, use of such a container for preparing adialysate is thus also claimed.

If substances that are not compatible are used to fill the container,the layers must be arranged with a distance between them according tothis invention. This may be accomplished either by a separation unit,e.g., a loose film or by another solid component. Preferably theincompatible components are separated from one another by a thirdcomponent which is itself compatible with each of the two othercomponents.

Compatible here is defined as not causing any mutual changes in theirchemical and/or physical properties whereas incompatible or notcompatible is defined conversely. This is understood to mean that thecontainer is also exposed to extreme ambient conditions such as thoseprevailing during sterilization, for example, over a long storage time.

If two layers of incompatible solids are kept a distance apart by meansof another solid, i.e., a third solid, then the latter may be in theform of small polymer beads, for example, which are themselves insolublein water while the other solids are water-soluble. However, it ispreferable for the third solid to be another component for producing adialysate which then is especially preferably in the form of granules,powders or crystals and is also water-soluble.

Examples of components that are used for preparing the dialysate includeelectrolytes, acids, sodium chloride, sodium bicarbonate and glucose. Ofthe substances, sodium bicarbonate and glucose, for example, are notmutually compatible. Therefore, according to this invention, a layer ofsodium chloride is placed between the layer of sodium bicarbonate andthe layer of glucose.

Any type of solid cartridge or flexible bag is conceivable as thecontainer; it should be made of a material that is also compatible withits ingredients. In the field of medical technology, in the past mainlysolid cartridges made of polycarbonate or flexible bags made ofpolyvinylpyrrolidone have been provided for this purpose. However, thesehave been replaced to an increasing extent by polyolefins, especiallypolypropylene and polyethylene, in combination with synthetic rubbers.Special coatings which additionally provide a gas barrier or a watervapor barrier and offer special compatibilities or similar advantagesare described in numerous variations in the state of the art.

The container should have at least one inlet to be able to fill it withthe components. According to this invention, this inlet may also be usedas an outlet at the same time. However, it is also conceivable for theinlets and outlets to be provided separately and/or for multiple inletsand/or outlets to be provided. These containers may also haveconnections, such as injection ports and ventilation and aerationdevices or the like.

According to this invention, the solids are added to the container inlayers. In order for the layers not to slip during storage, it isadvantageous for the layers to be secured in place. It is conceivablehere for a covering plate to be pressed onto the layers of solids andfor such a plate to be lockable. However it is especially advantageousfor unneeded gases or liquids to be removed from the container, e.g., bysuction.

For this reason the preferred embodiment of this invention is a flexiblebag in which a vacuum is created with the help of a pump after addingthe solids layer by layer and which is then sealed airtight. It shouldbe noted here that a space that is completely empty of air can never beformed, which is why the correct description refers to an interior spaceof the bag which contains the smallest possible amount of gas or fluid.Likewise, the embodiment as a flexible bag is not absolutely necessarybut it is especially helpful if the solids contained in the bag are tobe secured in place with the help of a “vacuum pack.”

Securing the solids at their location inside the bag serves to preventmixing of the solids so that incompatible solids cannot come in contactwith each other. Although this invention is not limited to the use ofsolids for producing a dialysate, the preferred embodiment isnevertheless a flexible container which is filled with preferably allthe substances required to prepare a dialysate, but at least is filledwith solids that form a partial concentrate.

One conventional partial concentrate is prepared by using threesubstances, namely bicarbonate, sodium chloride and glucose. Glucose issubject to degradation when it comes in contact with an incompatiblesubstance that has a basic pH, i.e., bicarbonate in this case. This iseven more the case during hot steam sterilization. When two incompatiblesubstances such as sodium bicarbonate and glucose as in this case areused for the partial concentrate, the especially preferred embodiment isa flexible bag having three layers of solids consisting of glucose,sodium chloride and sodium bicarbonate, with sodium chloride forming themiddle layer and the layers being secured in place by suction removal ofthe air in the interior of the bag.

Such a filled bag is used for supplying the concentrate used to preparethe dialysate. It is especially advantageous if the amount present inthe bag is just sufficient to prepare exactly the amount of dialysatenecessary and sufficient for one dialysis.

1. A container containing solids and having at least one inlet or outlet, characterized in that at least two different solids are arranged in layers.
 2. The container according to claim 1, characterized in that the solids are powders, crystals or granules.
 3. The container according to claim 1, characterized in that the solids are water-soluble.
 4. The container according to claim 1, characterized in that the at least two solids are not compatible with one another.
 5. The container according to claim 4, characterized in that the solids that are not compatible with one another are arranged in layers with a distance between them.
 6. The container according to claim 1, characterized in that the at least two solids that are not compatible with one another are separated from one another by a layer consisting of a third solid which is compatible with the at least two incompatible solids.
 7. The container according to claim 6, characterized in that the third solid is a powder, crystals or granules.
 8. The container according to claim 6, characterized in that the third solid is water-soluble.
 9. The container according to claim 1, characterized in that the water-soluble solids are selected from the group consisting of electrolytes, acids, sodium chloride, sodium bicarbonate and glucose.
 10. The container according to claim 6, characterized in that the third solid is sodium chloride.
 11. The container according to claim 6, characterized in that the third solid is water-insoluble.
 12. The container according to claim 6, characterized in that the third solid is polymer.
 13. The container according to claim 1, characterized in that the interior of the container contains as little gas and/or liquid as possible.
 14. The container according to claim 13, characterized in that the container contains the smallest possible amount of air.
 15. The container according to claim 1, characterized in that the container is flexible.
 16. A use of a container according to claim 1 for preparing a dialysate.
 17. The use of a container according to claim 1 for preparing a dialysate sufficient for exactly one dialysis. 